1. Field of the Invention
This invention relates to a dual type tension lock seat belt retractor provided with a so-called vehicle-sensitive emergency locking mechanism and a so-called webbing-sensitive emergency locking mechanism and having take-up force locking means for diminishing or nulling a take-up force, i.e. tension, applied to webbing while the belt is being worn.
The vehicle-sensitive emergency locking mechanism is a mechanism in which, when a deceleration over a predetermined value has occurred to a vehicle, sensing means is displaced and this displacement brings a lock member to a lock position to prevent rotation of webbing take-up reel shaft means in webbing draw-out direction, and the webbing-sensitive emergency locking mechanism is a mechanism in which, when by draw-out of the webbing, reel shaft means receives an angular acceleration over a predetermined value or reaches an angular speed over a predetermined value, sensing means senses this and brings a lock member to a lock position to prevent rotation of the reel shaft means in webbing draw-out direction.
2. Description of the Prior Art
Heretofore, various dual type retractors have been proposed to ensure safer wearing of the belt while, on the other hand, various tension lock retractors have been proposed to meet the requirement for comfortable wearing of the belt. Most of the conventional tension lock retractors are combined with a vehicle-sensitive emergency locking mechanism, and a dual type tension lock retractor does not yet exist because of the technical difficulty involved in realizing it.